I personally love cats and can identify with the realistic parts of these drawings. However, if you have been watching the animated versions of these drawings on youtube you might find them a little lacking.
Bought for my 6 year old son who has endless fun watching simon's cat; I was concerned the book wouldn't hold his attention but he laughs just as much at it as he does at the animated version! It was a stocking filler present and although we've probably seen all of simon's cats antics a hundred times we're not bored yet!! :-D